Nioh 3 Co-op Multiplayer Connection Error and Network Timeout Fix

What is the Nioh 3 co-op connection error?

Nioh 3's co-op multiplayer uses a peer-to-peer (P2P) networking model through Steamworks, meaning connection quality depends directly on both players' network configurations. Players encounter errors like "A connection error has occurred," "Session expired," or simply cannot find each other's rooms when trying to play together. The Torii Gate and Expedition co-op modes are particularly affected, with the Friends filter frequently showing "no available sessions" even when your friend is actively hosting.

Since Nioh 3's simultaneous PC launch on February 6, 2026, co-op connection issues have flooded Steam forums. The primary culprits are strict NAT types blocking P2P connections, missing port forwarding rules, version mismatches after hotfixes, and the game's unreliable friends list matching system.

When does it occur?

• When joining a friend's co-op session through the Torii Gate
• During Expedition matchmaking with the Friends filter
• After a game hotfix when one player hasn't updated yet
• On networks with strict NAT type (NAT Type 3/Strict)
• When the host's firewall blocks incoming P2P connections
• Approximately 10 seconds after successfully entering a room (connection drop)

Common causes

• Strict NAT type — NAT Type 3 (Strict) prevents incoming P2P connections entirely; Nioh 3 requires NAT Type 2 (Moderate) or ideally NAT Type 1 (Open) for reliable co-op
• Missing port forwarding — the host's router does not forward the ports required by Steam and Nioh 3's netcode
• Game version mismatch — hotfixes create version incompatibilities between players; both must be on the exact same build
• Friends filter bug — the Friends-only session filter is unreliable and often fails to display available sessions
• Windows Firewall blocking — the game executable is not whitelisted for incoming connections
• Mission access mismatch — you cannot join a session for a mission you haven't unlocked yet in your own playthrough
• No crossplay support — Nioh 3 does not support cross-platform play between PC and PS5

Step-by-step fixes

1. Check NAT type and enable UPnP — Log into your router's admin panel (usually 192.168.1.1 or 192.168.0.1). Find the UPnP setting under NAT or Advanced settings and enable it. This allows the game to automatically open the ports it needs. Restart your router after making changes. Verify your NAT type is Open or Moderate.

1. Set up port forwarding for Steam and Nioh 3 — In your router's port forwarding section, add these rules using your PC's local IP address:

- TCP: 27015-27030, 27036-27037

- UDP: 4380, 27000-27031, 27036

This is especially critical if you are the session host. Guests connecting to a host typically need fewer port configurations.

1. Use Secret Code matching instead of Friends filter — The Friends filter is unreliable. Instead, have the host create an Expedition with "Private (Secret Code)" for both Guest Slots. The joining player searches for Expeditions and enters the same six-character code. Use an obscure code to avoid accidental matches with strangers.

1. Verify both players are on the same game version — In Steam, right-click Nioh 3 → Properties → Updates → ensure "Always keep this game updated" is selected. Both players should verify game file integrity: right-click → Properties → Installed Files → Verify integrity of game files. Restart Steam completely after verification.

1. Add Nioh 3 to Windows Firewall exceptions — Go to Settings → Privacy & security → Windows Security → Firewall & network protection → Allow an app through firewall → Change settings → Add another app. Browse to the Nioh 3 executable (typically C:\Program Files (x86)\Steam\steamapps\common\Nioh 3\nioh3.exe). Check both Private and Public network boxes.

1. Ensure mission access matches — You cannot connect to a session running a mission you haven't reached yet. Have the host switch to an early mission that both players have access to. Once connected, you can change missions together.

1. Change DNS to Google DNS — Open Settings → Network & Internet → your connection → DNS server assignment → Edit. Set Preferred DNS to 8.8.8.8 and Alternate DNS to 8.8.4.4. This can resolve DNS-related connection timeouts during matchmaking.

1. Restart Steam and perform a clean network reset — Close Steam completely (system tray → Exit Steam). Restart your router. Open Command Prompt as Administrator and run:

ipconfig /flushdns
netsh winsock reset

Restart your PC, launch Steam, and try co-op again.

If it still doesn't work

If connection issues persist after all fixes, both players should test with a different network to isolate whether the issue is ISP-related — some ISPs use carrier-grade NAT (CGNAT) that blocks P2P connections entirely, in which case a VPN with port forwarding support may be the only solution. Check the [Steam Community forums for Nioh 3](https://steamcommunity.com/app/3681010/discussions/) for known issues and developer updates. Team Ninja has historically released connectivity patches in the weeks following launch. Note that Nioh 3 does not support crossplay, so PS5 and PC players cannot join each other under any circumstances. For other Nioh 3 PC issues, see our guides on [DXGI_ERROR_DEVICE_REMOVED crash](/en/errors/nioh-3-dxgi-error-device-removed-crash) and [fatal error crash at launch](/en/errors/nioh-3-fatal-error-crash-black-screen-pc).